From SLM process parameters to performance: microstructure and mechanics of nanostructured titanium

• Process-structure–property relationships are established for Ti NPs in SLM via MD. • Laser power, scan speed, hatch spacing, and substrate temperature are probed. • Optimized energy input enhances densification and mechanical performance. • Substrate preheating boosts atomic diffusion kinetics, leading to stronger products. • MSD analysis connects atomic mobility to defect reduction and mechanical features. Titanium (Ti) and its alloys are widely employed in dental implants because of their outstanding mechanical properties and biocompatibility. Recently, selective laser melting (SLM), as a widely adopted additive manufacturing (AM) technique, has gained significant attention for producing medical devices, including implants with complex geometries and high dimensional precision. In SLM, precise adjustment of processing parameters is essential to control microstructure and optimize performance. Despite extensive experimental and numerical efforts, a comprehensive atomic-scale understanding of how SLM process parameters collectively influence microstructure evolution, porosity formation, atomic dynamics, and mechanical behavior in pure Ti remains limited. In this study, molecular dynamics (MD) simulations were utilized to bridge this knowledge gap by systematically examining the critical SLM parameters affecting the microstructural, dynamic, and mechanical responses of nanostructured Ti. Results, validated against experimental observations, revealed that laser power, scan speed, and substrate temperature critically influence Ti microstructures and strength. Increasing power up to 400 eV and substrate preheating enhanced densification and reduced porosity, while excessive scan speeds (>2 Å/ps) caused defect-induced reductions in strength. This study clarifies the relationships between SLM parameters, microstructural evolution, and mechanical response, offering transferable design insights for tailoring process conditions to achieve optimized properties in Ti-based biomedical components.